| 1. |
- Leo, G. D., et al.
(author)
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Accurate measurement of Kinetic Friction Coefficient by using two types of tribometer
- 2019
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In: I2MTC 2019 Proceedings. - 9781538634608
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Conference paper (peer-reviewed)abstract
- Tribological tests are adopted to estimate the kinetic friction coefficient of the material of interest according to the ASTM standard. Typically, for the measurement process, several replicas as well as a post-processing data treatment are necessary to take into account the observed casual variability of the measurand. The paper describes a statistical approach for both Time and Frequency Domain analysis, aiming to highlight the most significant time intervals during each test replica. Experimental activity has been carried out by performing multiple tests through two different tribometers (ball-on-flat and ball-on-disk configurations) in order to verify the improvement allowed by the authors' proposal about the dry friction coefficient measurement in terms of both accuracy and reliability.
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| 2. |
- Carratù, M., et al.
(author)
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A Sound Level Meter featured with automatic estimation of the measurement uncertainty
- 2022
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In: Measurement. - : Elsevier BV. - 0263-2241 .- 1873-412X. ; 188
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Journal article (peer-reviewed)abstract
- In the area of measuring the environmental noise the equivalent sound pressure level LA,eq is adopted and compared with legal thresholds in order to characterize the site of interest. The paper describes an innovative Sound Level Meter (SLM) able to provide information about the measurand contribution to the measurement uncertainty estimation. This measurement technology is made possible thanks to an approach based on bootstrap method for selecting the suitable measurement episode for an estimation of LAeq. The firmware implementation of the developed SLM is disclosed with reference to a low-cost platform for real-time execution of the proposed methodology. Finally, a metrological characterization of the prototype performed in laboratory is reported as well as the performance comparison with a class 1 SLM in a real scenario. As a result, the smart features of the new SLM may be easily implemented by including commercial devices into the instrument schematics.
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| 3. |
- Liguori, Consolatina, et al.
(author)
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A Commentary on the Role of Noise Measurement Uncertainty in the Industrial Context
- 2021
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In: Lect. Notes Mech. Eng.. - Cham : Springer Science and Business Media Deutschland GmbH. - 9783030719555 ; , s. 324-331
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Conference paper (peer-reviewed)abstract
- This commentary highlights the importance of uncertainty and estimation associated with the measurement of noise levels in the industrial field. As example evaluating noise workers’ exposure in a workplace has to take into account levels of uncertainty. The authors investigated the effect of the variability of the measurand with respect to the uncertainty of the measurement and proposed a novel data-driven sampling approach which consists of three phases. Firstly, because the reliability of the noise indicators assessment depends significantly on the temporal variability of the noise, a statistic procedure is proposed to locate a corresponding minimum number of sound pressure levels necessary for having statistical significance of the initial data set. Next, a numerical algorithm finds and deletes the anomalous values (outliers) from a population of real data. Finally, the inherent variability of uncertainty of acoustic noise is calculated using the normal bootstrap method. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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| 4. |
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| 5. |
- Liguori, Consolatina, et al.
(author)
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Choosing Bootstrap Method for the Estimation of the Uncertainty of Traffic Noise Measurements
- 2017
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In: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 66:5, s. 869-878
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Journal article (peer-reviewed)abstract
- The environmental acoustic noise is considered as a big risk for today's population health. Consequently, the regulations in many countries commit themselves to control the exposition of people, imposing limits to the noise level. In the comparison between the measured value and the threshold, the uncertainty of the measured value has to be taken into account. In this paper, a procedure for the evaluation of the uncertainty of traffic noise measurements due to the variability of the measurand is proposed. A deep analysis of five bootstrap (normal, basic percentile, t-student, bias corrected percentile, and bias corrected and accelerated percentile) methods is performed to obtain accurate confidence intervals for the indicator Leq.Awithout necessity to make normal theory assumptions. From the comparison with the classical method (according to Guide to the Expression of Uncertainty in Measurement (ISO GUM)), the novel approach reveals to be more effective for estimating both the expected value and the uncertainty of the short-term equivalent sound pressure level when a large data set is not available.
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| 6. |
- Liguori, Consolatina, et al.
(author)
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Influence of measurement time on acoustic noise uncertainty
- 2017
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In: Proceedings of the 2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). ; , s. 1-6
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Conference paper (peer-reviewed)abstract
- In the paper the influence of the measurement time on the measurement uncertainty of environmental noise is explored. An original procedure based on a bootstrap method is introduced to determine the minimum measurement time, which takes into account the statistical variability of the acquired sound pressure levels. The experimental verification against real data about three different environmental noise sources shows the reliability of the algorithm for the prediction of the short-term noise indicator corresponding to longer time window.
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| 7. |
- Ruggiero, A., et al.
(author)
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Accurate Measurement of Reciprocating Kinetic Friction Coefficient through Automatic Detection of the Running-In
- 2020
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In: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:5, s. 2398-2407
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Journal article (peer-reviewed)abstract
- Tribological tests are adopted to estimate the kinetic friction coefficient (COF) of the material of interest according to the American Society for Testing and Materials (ASTM) standard. Typically, for the measurement process, several replicas, as well as a postprocessing data treatment, are necessary to take into account the observed casual variability of the measurand. This article describes a statistical approach aiming to highlight the running-in phase and the most significant time intervals during the steady-state for each test replica. A two-steps procedure based on the adoption of the bootstrap method allows the automatic detection of the running-in time interval and the outlier filtering of the steady-state. Experimental activity has been carried out by performing multiple tests through the ball-on-flat tribometer in order to verify the improvement allowed by the authors' proposal about the dry friction COF measurement in terms of both accuracy and repeatability. © 1963-2012 IEEE.
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